Hydromechanical final drive

Abstract

A hydromechanical drive having a fixed hub support and a rotary hub, a hydrostatic swash-plate type axial piston motor and a planetary gear connected to the output side of the rotary hub. A control surface is formed on the hub support and pressure medium conduits are formed in the hub support and open on the control surface to provide pressurized hydraulic fluid to the axial piston motor. A cylindrical machine part surrounds the cylindrical drum of the axial piston motor and is non-rotatably connected to the rotary hub. A bearing is located between the inner surface of the rotary hub and the outer surface of the hub support to absorb forces from the axial piston motor and from outside the drive.

I claim: 
     
       1. A hydromechanical final drive having a fixed hub support with a cylindrical outer surface and an annular rotary hub with a cylindrical inner surface and an output side, a hydrostatic swash-plate type axial piston motor having a cylindrical drum with an outer surface and an inner surface, a plurality of work cylinders located within said cylindrical drum and a work piston located in each of said plurality of work cylinders, a planetary gear having an axial length located within the axial length of said piston motor and connected to the output side of said rotary hub, said planetary gear and said cylindrical drum being coaxial, a control surface formed on said fixed hub support, pressure medium conduits formed in said fixed hub support and having outlets opening on said control surface and in flow connection with said plurality of work cylinders in said cylindrical drum, a cylindrical machine part surrounding said outer surface of said cylindrical drum and non-rotatably connected to said rotary hub, whereby said cylindrical drum is non-rotatably connected directly to said cylindrical machine part, and a bearing located between said cylindrical inner surface of said rotary hub and said cylindrical outer surface of said fixed hub support for absorbing forces of said axial piston motor and outside forces affecting the final drive. 
     
     
       2. A hydromechanical final drive as set forth in claim 1, including a sun gear in said planetary gear, a ring gear connected to said fixed hub support, and a web connected to said cylindrical machine part. 
     
     
       3. A hydromechanical final drive as set forth in claim 2, wherein said cylindrical drum has an end surface axially spaced from said control surface and said sun gear is located axially between said end surface of said cylindrical drum facing said control surface and said control surface, and a plurality of spaced openings formed in said sun gear for periodically connecting said outlets of said pressure medium conduits in said control surface with said plurality of work cylinders in said cylindrical drum. 
     
     
       4. A hydromechanical final drive as set forth in claim 3, wherein said cylindrical machine part is the sun gear of a second stage of said planetary gear, a ring gear in said second stage of said planetary gear connected to said fixed hub support, and said second stage of said planetary gear including a web connected to said rotary hub. 
     
     
       5. A hydromechanical final drive as set forth in claim 3, including a tie rod having an outer surface and extending through and coaxial with said cylindrical drum, a swash plate connected to said tie rod, means for non-rotatably connecting said tie rod to said fixed hub support in the area of said control surface, and a bearing located between said outer surface of said tie rod and said inner surface of said cylindrical drum adjacent to said swash plate. 
     
     
       6. A hydromechanical final drive as set forth in claim 4, including a tie rod having an outer surface and extending through and coaxial with said cylindrical drum, a swash plate connected to said tie rod, means for non-rotatably connecting said tie rod to said fixed hub support in the area of said control surface, and a bearing located between said outer surface of said tie rod and said inner surface of said cylindrical drum adjacent to said swash plate. 
     
     
       7. A hydromechanical final drive as set forth in claim 5, wherein said cylindrical drum is mounted on the end of said tie rod spaced from said control surface. 
     
     
       8. A hydromechanical final drive as set forth in claim 3, including brake means for said rotary hub located within said fixed hub support. 
     
     
       9. A hydromechanical final drive as set forth in claim 4, including brake means for said rotary hub located within said fixed hub support. 
     
     
       10. A hydromechanical final drive as set forth in claim 5, including brake means for said rotary hub located within said fixed hub support. 
     
     
       11. A hydromechanical final drive as set forth in claim 6, including brake means for said rotary fixed hub located within said hub support. 
     
     
       12. A hydromechanical final drive as set forth in claim 7, including brake means for said rotary fixed hub located within said hub support. 
     
     
       13. A hydromechanical final drive as set forth in claim 8, wherein said brake means includes at least one brake plate non-rotatably and axially slidably connected to said web of said planetary gear and at least one brake plate non-rotatably and axially slidably connected to said fixed hub support, and means for moving said at least one brake plate connected to said web axially to contact said at least one brake plate connected to said hub support. 
     
     
       14. A hydromechanical final drive as set forth in claim 1, wherein said bearing located between said fixed hub support and said rotary hub is a double-row annular ball bearing. 
     
     
       15. A hydromechanical final drive as set forth in claim 2, wherein said bearing located between said fixed hub support and said rotary hub is a double-row annular ball bearing. 
     
     
       16. A hydromechanical final drive as set forth in claim 8, wherein said bearing located between said fixed hub support and said rotary hub is a double-row annular ball bearing. 
     
     
       17. A hydromechanical final drive as set forth in claim 13, wherein said bearing located between said fixed hub support and said rotary hub is a double-row annular ball bearing.